Case Studies

VW Jetta Diesel TDI – Dual Mass Flywheel Failure

Great idea, poor implementation. Sometime back in the early 1990s Porsche tried this in the 911 series, it did not work out well then, and it seems not to have worked well now. The dual mass flywheel is composed of two parts, damaged with silicone to soften engine noise and impact shock during clutch engagement. Often, with older and high mileage cars, the silicone and damping material fail on the dual mass flywheel, resulting in engine noise, vibration, and excessive lash in the driveline when engaging the clutch. This vehicle experienced the failure at about 50K miles, really quite low as far as clutch life normally goes, but apparently quite common with the dual mass design.

The repair can be approached two different ways, taken from either a cost or durability standpoint. The costly method, and one which we feel not to be durable, is the installation of the same expensive dual mass flywheel unit, with the attendant failure problems down the road. We suggest the replacement and update of the complete clutch assembly to a solid flywheel design. The proper solid flywheel replacement has the approximately the same mass as the dual mass set up, so the exchange is all but transparent to the driver. Aside from the cost benefits, durability is of course improved with the solid design, as there is no longer any damping material to leak out, or become damaged. The photos below show the original dual mass set up, and the replacement, solid flywheel kit. Note the use of multiple discreet damping springs in the clutch disc on the solid flywheel unit, this takes the place of the damping material in the dual mass flywheel.